1. Technical Field
The present disclosure relates to control devices and control methods, and more particularly, motor control devices and motor control methods.
2. Description of Related Art
Conventional sinusoidal pulse-width modulation (SPWM) for driving motor is based on the comparison between a sinusoidal voltage command generated by a controller and a triangular wave. Specifically, the pulse width is controlled by comparing a reference signal with a carrier signal having a higher frequency, and thereby, the conducting or cut-off time of the power semiconductor in the inverter is determined. For example, during an SPWM modulation, a sinusoidal wave (Vs) is used as the reference signal, and a triangular wave (Vt) is used as the carrier wave; when Vs>Vt, a pulse-width modulation signal with a high logic level is generated; in contrast, when Vs<Vt, a pulse-width modulation signal with a low logic level is generated.
The implementation of the aforementioned SPWM modulation is quite simple; for example, an analog circuit may be used as a generation circuit for generating the triangular wave and the sinusoidal modulating wave; a comparator may be used to ascertain the crossover point of the two waves; and a SPWM wave could be generated by controlling the on/off state of the switch at the crossover time. However, such analog circuit is quite complex in structure, and therefore, is not feasible in achieving an accurate control.
In view of the foregoing, there still exist some inconveniences and defects in conventional motor-driving methods that await further improvement. However, those with skilled in the art sought vainly for a solution. In order to solve or circumvent above problems and disadvantages, there is an urgent need in the related field to provide a more accurate method for controlling motors.